There has been conventionally known a chain saw as equipment for performing tree-cutting, tree-pruning, branch-trimming and the like. The chain saw includes a flat-plate shaped guide bar, a body supporting the guide bar, and a handle connected to the body and gripped by an operator. An engine for driving a saw chain wound around the guide bar is housed in the body. Also housed in the body are an oil tank, a fuel tank, a muffler and the like for the engine. As examples of such a chain saw, there are top handle type chain saws in which the handle is provided above the body (refer to, for example, Document 1; Patent Publication No. 3186836, and Document 2: Japanese Utility Model Laid-Open No. Hei2-34725).
However, in these chain saws, since an exhaust outlet for discharging the exhaust from the muffler is arranged on a lateral side of the body, the exhaust is discharged to the lateral side of the body. Accordingly, when the exhaust is discharged, exhaust sound is easy to be propagated to the operator, therefore good work environment can not be achieved.